High rates of infections and re-infections of soil transmitted helminthes (STHs) is a public health challenge perhaps due to resistance to anthelmintics in STHs endemic areas. This public health challenge necessitates renewed efforts to discovering newer agents. This study evaluated the ovicidal and larvicidal activities of methanol leaf extract of Jatropha curcas against Ascaris suum. The plant’s material was collected, pulverized and extracted by cold maceration using 70% methanol, and qualitative analyzed for phytochemicals. Graded concentrations (25, 50 and 100 mg/ml) of the extract were tested for Ascaris suum egg’s hatch inhibition (EHI) and larvae development inhibition (LDI). Distilled water and 1 mg/ml albendazole served as negative and positive controls, respectively. The extract caused a dose-dependent EHIs of 82.57, 89.44 and 92.08% inhibitions at 25, 50 and 100 mg/ml, respectively. In addition, larvae development was inhibited by 91.72, 95.52 and 98.11% at 25, 50 and 100 mg/ml, respectively. The EHI and LDI of the extract at 100 mg/ml was not significantly different (p<0.05) relative to albendazole that produced EHI and LDI of 94.01 and 99.14%, respectively. The phytochemical detected were alkaloids, glycosides, flavonoids, saponins, steroids, and tannins. Jatropha curcas extract demonstrated excellent anthelmintic activity justifying its uses in ethno-medicine.